38 COLORATION IN POUSTES. 



VARIATIONS IN OTHER SPECIES OF POLISTES. 



The three species just considered, together with their allies, com- 

 prise the principal representatives of the genus in the United States. 

 Occurring scatteringly throughout southern United States are three 

 other types. These are, first, a prominently xanthic type, whose prin- 

 cipal representative is P. flavus and which occurs in the arid region of 

 Arizona and New Mexico ; second, a more or less uniformly colored 

 melanic type, represented by P. annularis and P. canadcnsis and scat- 

 tered through southern United States ; and, third, a series of reddish- 

 brown forms occurring in southern and southeastern United States, 

 comprising a great assemblage of forms, which will be named in fol- 

 lowing paragraphs. 



Concerning the first, no detailed study of individual variation has 

 yet been made in this species. Its coloring is cinnamon brown, with 

 large metameric spots confluent with the broad yellow borders. The 

 few specimens examined show variation in the depth of the brown 

 coloring and its area of distribution. Concerning the second, some 

 doubt has been expressed by De Saussure as to the reality of the dis- 

 tinction between the two species annularis and canadcnsis. Collections 

 for the United States exhibit considerable variation in the extent and 

 distinctness of their markings. They differ from each other mainly in 

 the possession by annularis of a prominent terminal border on the first 

 abdominal segment ; in canadensis all the segments may have a narrow 

 terminal border, and many transitions exist between this condition and 

 a uniform dark fuscous or black coloring for the abdomen. Examina- 

 tion of any series of specimens which vary thus shows that the borders 

 of the posterior segments tend to disappear first, and even after the 

 borders of all the other segments have become obsolete the most ante- 

 rior one is found to remain distinct and prominent. This tendency is 

 particularly striking in the variable species of lincatus and pallipes, and 

 from this we see how such a species as annularis might arise by the 

 fixing of a slight individual variation. 



The third class, consisting of red-brown forms, comprises a great 

 number of species occurring in the Gulf and South Atlantic States. 

 They are especially well represented in Texas, where they have been 

 collected and studied by Mr. E. T. Cresson. It will be convenient to 

 separate these forms into two great groups, which differ mainly in point 

 of size, and which we will denominate respectively as the texanus-rubi- 

 ginosus and the carolinus type. They will be considered separately. 



